Is it safe to continue to connect a dryer to a 40 Amp circuit?

In the process of planning to move my Maytag dryer from the main floor to my basement I found out that this Maytay dryer (5 month old) and the previous dryer (about 10 year service life) had been connected to a 40 Amp circuit (40 Amp circuit breaker and 8-gauge cable, 3 prong receptacle).
According to the Maytag dryer manual, the dryer should have been connected to 30 Amp circuit, 10-gauge cable, 3 prong. However, since these 2 dryers had been and currently being connected to this 40 amp circuit for a long time (at least 10 years since the day that I moved in and probably 20 years since the house was built) and nothing happened, I dont know if I should replace the 40 amp circuit breaker and 8-gauge cable with a 30 amp circuit breaker and 10-gauge cable when I move the dryer to the basement?
If it is safe I really want to use the same 40 amp circuit breaker and connect a junction box to the current 8-gauge cable and extend a new 8-gauge cable from the junction box to a new receptacle at the new place of the dryer in the basement.
Thank you in advance for your help.

 

I dont think you can splice that wire legal. If you run a new 10 wire use 10/3 wg though. It was legal to use 3 wire because it was existing. You could have just changed the breaker to a 30,,, but it work on that 40 just fine too. The breaker is desined to protect the wire,, but its a good idea to get it as close to the equipment requirements as you can. So,,, run new 10 wire and look in directions for removing bonding strap in dryer. You should get new cord and recept. New dryers are sposed to be 4 wire,,, unless you have existing 3 wire power supply,,, but ,, you are changing location,, means new supply.

 

You cannot extend the 3 wire dryer circuit.You will have to run a new 4 wire circuit to the basement. It will have to minimum of # 10 wire. It is not OK to use a 40 amp breaker for a dryer outlet.The receptacle is rated for 30 amps and cannot be protected by a larger amperage breaker.The manufacturer also requires a 30 amp breaker.Even though it has worked that way for 20 years,it still makes it an unsafe circuit when protected by too large a circuit breaker.The breaker is sized to protect the wire,the receptacle,and the dryer.